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CVE-2024-45337 is a critical authorization bypass vulnerability affecting applications and libraries that misuse the Go programming language standard library package crypto/ssh, specifically concerning the callback field ServerConfig.PublicKeyCallback. During the SSH handshake process, documentation historically indicated that PublicKeyCallback would be invoked in a specific sequence; however, applications often mishandled the callback state across multiple verification attempts. This architectural misunderstanding allowed malicious clients to supply manipulated public key presentation sequences where authentication decisions were inadvertently bound to an incorrect key index controlled by the attacker. Because this specific API pattern was widely adopted across various open-source Go projects and SSH server implementations, traditional static vulnerability scanners frequently flagged dependencies as vulnerable. However, many reported instances were false positives because the vulnerable code paths were never actually reachable or compiled into execution paths within the codebase. To address this alert fatigue and triage overhead, Xpsd v1.0.0 was released as an automated LLM-driven reachability triage agent. Operating seamlessly via GitHub Copilot through the workflow’s built-in GITHUB_TOKEN or custom LLM API keys for OpenAI, Anthropic, and Azure, Xpsd ingests standard SARIF 2.1.0 reports generated by scanners such as Grype, Trivy, OSV-Scanner, and Snyk. The agent reads the source tree directly, analyzes call graphs and dependencies, and determines with high precision whether the vulnerable functions are actively reachable in the project. It then outputs enriched SARIF files for the GitHub Security tab alongside per-finding verdict JSON files and detailed markdown reports. By combining automated reachability analysis with deep code inspection, development teams can accurately distinguish between theoretical vulnerability flags and genuinely exploitable code paths without manual auditing.
DailyCVE Form:
Platform: Go runtime
Version: Below v0.31.0
Vulnerability : Authorization bypass
Severity: Critical
date: December 2024
Prediction: Already patched completely
What Undercode Say:
To execute Xpsd for automated reachability triage and process SARIF vulnerability scan reports directly within your local development environment or containerized CI/CD workflow, you can utilize the official Docker container image release:
docker run --rm -v $(pwd):/workspace ghcr.io/byteray-ai/xpsd:1.0.0 --sarif /workspace/report.sarif
For native GitHub Actions integration using the repository’s built-in GITHUB_TOKEN without requiring separate LLM API keys, configure your workflow YAML file as follows:
name: Xpsd Vulnerability Triage on: pull_request: branches: [ main ] jobs: triage: runs-on: ubuntu-latest permissions: contents: read security-events: write steps: - name: Checkout repository uses: actions/checkout@v4 - name: Run Xpsd Reachability Agent uses: byteray-ai/xpsd@v1 with: sarif-file: 'report.sarif'
Exploit: (Educational Purposes!)
An attacker exploits CVE-2024-45337 by targeting applications that improperly handle Go’s crypto/ssh PublicKeyCallback logic. During the SSH public key authentication handshake, the malicious client transmits a specially constructed sequence of public keys. Due to flawed authorization checks in the application’s callback implementation—which incorrectly assumes key validation order or shares state across attempts—the server evaluates and accepts an intermediate or secondary key for authorization. Because the attacker controls the private key corresponding to the accepted session validation state, the SSH server grants unauthorized remote access or session privileges, bypassing security controls entirely.
Protection: from this CVE
Upgrade the Go standard library dependency to version v0.31.0 or higher, which enforces strict invariants ensuring that the final successfully authenticated public key is definitively bound to the session authorization decision. Additionally, integrate reachability analysis tools like Xpsd into your CI/CD pipelines to scan and verify whether vulnerable dependency code paths are actually compiled and reachable in your source tree, ensuring security teams focus exclusively on actionable vulnerabilities.
Impact:
Successful exploitation of CVE-2024-45337 results in a complete authentication bypass on affected SSH servers and network libraries, allowing unauthenticated remote attackers to gain unauthorized administrative or operational access to vulnerable systems. Furthermore, unmitigated vulnerability scanner noise can overwhelm engineering teams with false positives, which tools like Xpsd successfully alleviate by filtering out unreachable findings.
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Sources:
Reported By: github.com
Extra Source Hub:
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